Drum-type washing machine

ABSTRACT

A drum-type washing machine employs a plurality of lifts each having a curved portion and a concave recess, to improve washing performance, decrease washing time, and reduce a vibration and noise occurring during high-speed operation. The drum-type washing machine includes a drum for receiving laundry, the drum having an inner circumferential surface and being rotatable about a central axis; a rotational shaft coupled to the drum for transferring a rotational force to the drum; and a plurality of lifts mounted to the drum and installed at intervals around the inner circumferential surface, each lift having a predetermined length with respect to the central axis of the drum and having an overall curved configuration formed by a curved portion disposed toward the rotational shaft, the overall curved configuration consisting of an inner side and an outer side. The concave recess may be formed on one or both sides of the lift.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a drum-type washing machine, and moreparticularly, to a drum-type washing machine employing a lift having acurved portion and a concave recess.

2. Discussion of the Related Art

Generally speaking, laundering using a drum-type washing machine iscarried out using a frictional force between the laundry and a rotatingdrum that receives the driving force of a motor. Such a method causeslittle damage to the laundry, prevents the laundry from getting tangled,and achieves such washing effects as beating and rubbing.

FIG. 1 illustrates a drum-type washing machine according to a relatedart, having a plurality of lifts 1 axially installed on the innercircumferential surface of a drum. An example of such a lift is shown inFIG. 2.

Referring to FIG. 1, a cylindrical drum 2 for holding and washinglaundry is mounted within a tub 8 for holding washing water, such thatthe drum lies parallel with respect to a foundation. A rotational shaft7 is connected to the drum 2 to rotate the drum forwardly and reversely,thereby enabling the laundry to be washed inside the drum. This rotatingaction results from a rotating force transferred to the drum 2 using anelectrical motion system made up of a motor 3 that drives a belt 5linking a pair of pulleys 4 and 6, thus allowing full directionalcontrol of the rotation of the drum.

Each lift 1 has a regular trapezoidal cross-section, and when mounted onthe drum 2, extends in parallel with the rotational shaft 7. In additionto the parallel configuration, each lift 1 has a pair of inclined sides1 a and 1 b that are substantially planar.

In the operation of a drum-type washing machine constructed as above,laundry is placed in the drum 2, water is supplied to the tub 8, and therotational shaft 7, driven by the motor 3, rotates the drum. As the drum2 rotates, the laundry is lifted by at least one of the lifts 1, from alower area of the drum's interior and up one side of the interior, untilreaching a point where the inclined side 1 a or 1 b passes a plane levelto the foundation, whereupon the lifted laundry falls back down to thedrum's lower area. The laundry is thus washed by a combination ofactions occurring in the washing water, including the drum's rotationand the laundry's lifting and falling. As the drum 2 rotates, thelaundry is lifted and falls to produce a sudsing action in the washingwater.

In the drum-type washing machine according to the related art, theconfiguration of the inclined sides 1 a and 1 b, i.e., the parallelorientation and planar side surfaces, provide limited frictional forceon the laundry. As a result, the lifting action is also limited, so thatthe laundry slides from the lift too soon, to fall only a shortdistance, which creates only a light sudsing action. Optimum washing,however, requires vigorous sudsing.

As above, the lifting ability of the lifts of the drum-type washingmachine of the related art is insufficient. Therefore, the washingperformance of the drum-type washing machine of the related art is lessthan optimum.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a drum-type washingmachine having a lift that substantially obviates one or more problemsdue to limitations and disadvantages of the related art.

An object of the present invention is to provide a drum-type washingmachine employing a lift having a curved portion and a concave recess,by which washing performance is improved, washing time is decreased, anda vibration and noise occurring during high-speed operation is reduced.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows, and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thespecification and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein,there is provided a drum-type washing machine comprising: a drum forreceiving laundry, the drum having an inner circumferential surface andbeing rotatable about a central axis; a rotational shaft coupled to thedrum for transferring a rotational force to the drum; and a plurality oflifts mounted to the drum and installed at intervals around the innercircumferential surface, each lift having a predetermined length withrespect to the central axis of the drum and having an overall curvedconfiguration formed by a curved portion disposed toward the rotationalshaft, the overall curved configuration consisting of an inner side andan outer side. The concave recess may be formed on one or both sides ofthe lift.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and illustrative and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a schematic cross-sectional side view of a drum-type washingmachine according to a related art;

FIG. 2 is a perspective view of a lift in FIG. 1;

FIG. 3 is a schematic cross-sectional side view of a drum-type washingmachine having a plurality of lifts according to a first embodiment ofthe present invention;

FIG. 4 is a perspective view of one of the lifts shown in FIG. 3;

FIG. 5 is a schematic cross-sectional side view of another drum-typewashing machine, wherein the lifts according to FIG. 4 are mounted in analternative configuration; and

FIG. 6 is a perspective view of a lift according to a second embodimentof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Throughout the drawings, like elements are indicated using thesame or similar reference designations where possible.

FIG. 3 illustrates a drum-type washing machine according to a firstembodiment of the present invention, wherein a plurality of lifts areaxially installed on an inner circumferential surface of a drum. Anexample of the lift is shown in FIG. 4.

Referring to FIG. 3, a drum 20 having a cylindrical shape for receivingand washing laundry is mounted within a tub 80 for holding washingwater, such that the drum lies parallel with respect to a foundation. Arotational shaft 70 is connected to the drum 20 to rotate the drumforwardly and reversely, thereby enabling to wash the laundry inside thedrum. This rotating action results from a rotating force transferred tothe drum 20 using an electrical motion system made up of a motor 30 thatdrives a belt 50 linking a pair of pulleys 40 and 60, thus allowing fulldirectional control of the rotation of the drum.

Referring to FIG. 4, each of the lifts 10 has an overall curvedconfiguration formed by a curved portion disposed toward the rotationalshaft 70 and a concave recess 10 a for catching laundry formed in theentire length of the inner side of the curve. Each lift extends apredetermined length in the axial direction of the drum 20. The concaverecess 10 a is formed on the inner side of the curved portion. Duringoperation of the drum-type washing machine according to the presentinvention, laundry rotating with in the drum 20 will be caught in thecurved portion of each lift 10 and in the concave recess 10 a thereof.

During operation, as the drum 20 rotates forwardly and reversely, thelaundry is pulled up by the lifts 10 and then falls in a drop zone inthe interior of the drum 20, to perform a mechanical washing process.Since the portion of each of the lifts 10 near the rotational shaft 70is curved, the laundry can be lifted higher to fall, whereby a washingpower is improved. As the laundry is caught and lifted upward by thelifts 10, the concave recess 10 a enables a reduction in washing time,by pulling up more of the washing water and thereby soaking the laundrymore thoroughly.

Moreover, the overall curved configuration of the lifts 10 differs withrespect to the rotating direction of the drum 20. Thus, the drop zone ofthe laundry is varied as the drum 20 reverses its rotational direction.This variation enables a more thorough stirring action of the laundryand improves the washing power accordingly.

Meanwhile, contrasting moments are applied to the rotational shaft 70during operation, which are especially significant with larger loads.That is, a relatively great moment is applied to the rotational shaft 70by an eccentric weight of laundry disposed at the far end of the drum 20with respect to the rotational shaft 70, while a relatively small momentis applied to the rotational shaft 70 by an eccentric weight of laundrydisposed at the near end of the drum.

Hence, since each of the lifts 10 has the curved portion near therotational shaft 70 so that the laundry is distributed near therotational shaft 70 on a dewatering step, the moment applied to therotational shaft 70 by the eccentric weight of the laundry is decreasedto reduce the vibration and noise.

FIG. 5 illustrates another drum-type washing machine according to thepresent invention, wherein the lifts according to FIG. 4 are mounted inan alternative configuration. Here, the lifts 10 are installed so thatthe curved portions of adjacent lifts face each other, i.e.,symmetrically. In this manner, the washing action of the laundry isuniform regardless of the rotational direction of the drum 20.

Referring to FIG. 6, illustrating a lift 110 according to a secondembodiment of the present invention, a concave recess 110 a is formed onboth sides of each lift. Thus, regardless of the drum's rotationaldirection, as the laundry is caught and lifted upward by the lifts 110,the concave recesses 110 a enable a reduction in washing time by pullingup more of the washing water and thereby soaking the laundry morethoroughly, as in the case of the concave recess 10 a formed on one sideonly. Moreover, as with the lift configuration of FIG. 5, the lifts 110according to the second embodiment may likewise be configured so thatthe curved portions of adjacent lifts 110 face each other, to provideuniform washing power regardless of the rotational direction of the drum20.

By adopting a drum-type washing machine according to the presentinvention, several benefits arise, particular with respect to the curvedportion of the lift. That is, with the curved portion of each liftdisposed near the rotational shaft, washing performance is improvedsince the laundry is lifted higher to fall farther. Furthermore, thedisposition of the curved portion inherently distributes the laundrycloser to the rotational shaft on dewatering, so that the moment appliedto the rotational shaft by the eccentric weight of the laundry isdecreased to reduce vibration and noise. The curved portions also enablethe drop zone of the laundry to vary according to the rotationaldirection of the drum, to produce a more, thorough stirring action inthe laundry, whereby washing power is improved.

In addition, the concave recesses of the lifts enable more washing waterto be pulled up for soaking the laundry more thoroughly, to reducewashing time accordingly.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present invention. Thus,it is intended that the present invention covers such modifications andvariations, provided they come within the scope of the appended claimsand their equivalents.

1. A drum-type washing machine comprising: a drum for receiving laundry,said drum having an inner circumferential surface and being rotatableabout a central axis; a rotational shaft coupled to said drum fortransferring a rotational force to said drum; and a plurality of liftsmounted to said drum and installed at intervals around the innercircumferential surface, each lift having a predetermined length withrespect to the central axis of said drum and having an overall curvedconfiguration formed by a curved portion disposed toward said rotationalshaft, the overall curved configuration consisting of an inner side andan outer side.
 2. The drum-type washing machine as claimed in claim 1,wherein each of said plurality of lifts has a concave recess, formedalong the inner side of the overall curved configuration, for catchinglaundry rotating in said drum.
 3. The drum-type washing machine asclaimed in claim 1, wherein each of said plurality of lifts has aconcave recess, formed along both sides of the overall curvedconfiguration, for catching laundry rotating in said drum.
 4. Thedrum-type washing machine as claimed in claim 1, wherein said pluralityof lifts is installed so that the curved portions of adjacent lifts faceeach other.
 5. The drum-type washing machine as claimed in claim 4,wherein each of said plurality of lifts has a concave recess, formedalong the inner side of the overall curved configuration, for catchinglaundry rotating in said drum.
 6. The drum-type washing machine asclaimed in claim 4, wherein each of said plurality of lifts has aconcave recess, formed along both sides of the overall curvedconfiguration, for catching laundry rotating in said drum.